What sort of code reading strategies do you use?

it depends. Is it for comprehension or for critique?

if it’s for comprehension, i tend to work vertically. What makes field X display on screen, or sets a given field in an API request. Then work backwards to the source. I find that getting a broad understanding of a given subsystem is less helpful than seeing how the layers fit together at first.

For reviews it’s honestly a lot more “code smell”. I’d there something odd about the shape of code? Something that seems totally against idiom or standards? I do look at context, but normally during the grokking process for an “interesting” bit.

I follow the tips across these resources:

• How To Learn A New Codebase Fast
• Learning A New Codebase? Here's How To Figure Out What Matters
• "What’s the most effective way to switch domains in tech?"

Paraphrasing the points from above:

1. Find someone to give you a high-level overview of the codebase.
2. Identify the 1-5 most impactful classes/modules and read those.
3. Make changes to the code and add print statements everywhere. Then run it to see what happens. If you're working with front-end, you can just print messages directly to the UI (e.g. in Android, you can use the Toast library to spam debug info).
4. Understand how to "command click" in your IDE, so you can easily follow call chains.